Spark plug



June 23, 1925.

R..'. L. Si'OVER 'PARK PLUG.

Filed July 18, 1923 INVENTOR 7R4 5 rare/i;

ATTORNEYS WITNESSES V 9 specification.

through a slight modification of theiinven- Patented June 23, 1925 UNITED STA nor LI T'rnE I; srcvmi; or OKLAILIOMJA ci'ry, oKLAnoiy A,

: srARK Ptmph "Application filed luly 18, 1923 Serial No 652,396;

To all whom it may concern; I

Be it known that 1, Her Lrr'riiri m S'iovnu, a citizen of theUnited -States and resident of Oklahoma City, in the county vof Oklahoma and State of Oklahoma, have invented certain newand useful Improvements in Spark Plugs,-of which the following is a This invention relates to spark plugs especially adapted for use on internal combustionengines, l J p Briefly'stated an important object of this invention is to "provide a sparkplug having simple means to combat excess oil in the combustion chamber of theengine to create an extremely hot and-well distributed spark by means of which complete conihustion is assured.- I Y A further object is to provide a spar-l: plug in which the heat resulting from combustion is utilized to burn thecil on the spark plugs and thereby allow the spark plug-to continue rto operate.

A further object is to provide a spark plug which is of highly simplified construc-.

tion desirable in use andchea'p .to manufacture;v L

v Other objects and advantages will be apparent during the course of the following description; i p r g Q i In the accompanying drawing forming a part of this" application; and in which like numerals are employed to designate like partsthroughout the same, v v

Figural: is a side-elevation of theimproved spark plug in-use, I

Figure 2 is a vertical through the same,.

Figure 3 is a detail vertical sectional View sectional I view tion. a

i In the drawinq' wherein for, the pH i it w v l'liQcIltllG comoust on chamber to insure the I n b I v s of illustration is shown a preterred. embodi- -1nent of the invention, the numeralt jdesic,

nates a cylinderhaving the usual QOIlibll tion chamberfi and a piston 7 is mounted forg reciprocation in the cylinder, all ofv which, is illustrated in Figure ll. V

The improvedsparkiplug consists. of a shell generally designated :by the numeral 10 and having its forward portion threaded as? indicated atjgll for attachment to the. motor in the manner illustrated in Figure 1.

In carrying out the invention the shell 11., is provided at its forward end with an integral tubular extension or electrode 12 3- Figure formed j Of rather metal so that the samewillreadil-y absorb the heat incident *to' combustion and will therefore burn any oil-which may accumulate thereon.

' lfthecyli'nder to which the improved spark plug is connected is especially oily the exterior of; the tubular electrode may "be provided with: a series of annular fins 14 which ;readily-.heat and thereby efiiciently burn the oiliaccumulated on the shell It wlll be, seen w th reference to Figure 2 that the upper and lower surfaces and'the outer edges of the fins 14 are exposed to the heat thuscausing the oil to become quicklyheat- .ed and assist-in retaining a sufiicient amount of heat to gprevent oil-from accumulating thereon; i

- Also it will he seenthat oil prevented fromdripping down the outer surface of the shell and onto the lowerendof the tuibular electrode which constitutes one sideof asparkgapn- I a 2 illustrates that the central electrode 16 is extended through an insulatorilT andlhas its forward portion threaded for engagement with the boss 18 of a conc avoconvex bafileQO, the said bafiie being formed with anannular fiange'2l which constitutes one side ,of the spark gap carrying out the invention v the concavo-convex. baffle and electrode is held upon the s stem or, center electrode 16 by a nut25 and as the concavoconvexbaflie-and electrodeQO is threaded ,upon the stenr thespark gap may be readily adjusted;

As 'the annularflange 21 :is arranged din 4 recitly in advance of the forward end of the tubular] electrode 12 an annular spark gap is prolvided by means of which aihot and well distributedspark provided. Byreason o flthe'annular spark gap, the flame resultingifron the spark is distributed over complete combustion of the compressed fuel.

The convex side of the electrode 20 is presented upwardly so to provide an inclined drain by i-means of which 'anyioil which enters "the shel lOYmay .be returned to the combustion; chamber. 7 I v n hFigure 21 illustrates that the stem 16 is provided rearwardly of the electrode 20 and. within the tubular electrode 12 with an annular enlargement 30 in the form of a truncated cone, the base of which is arranged to obstruct the entrance of oil into the shell.

That is to say the lower side of the annular enlargement is arranged at right angles to the axis of the stem 16 while the upper side of the annular enlargement 30 inclines downwardly or is extended diagonally with respect to the axis of the stem 16 so as to allow the oil to freely drain should any en ter the shell.

Also the inner side of the shell is provided rearwardly of the annular enlargement 30 with an inwardly projecting annular rib 32 which cooperates with the annular enlargement 30 in preventing the entrance of oil into the shell. It will be seen that the inwardly projecting annular rib 32 is gradually tapered toward its inner free end and is inclined downwardly so as to obstruct the entrance of oil into the shell and toallow of complete discharge of the oil. wardly projecting annular rib 32 is rather thin it will become highly heated and will quickly burn any oil which may accumulate thereon.

Particular attention is invited to the fact that the concavo-convex formation of the electrode 20 not only provides for the escape of oil but also prevents the warping of the electrode as the result of the heat with which the same necessarily comes in contact.

In operation the members 30' and 32 are called upon especially when the motor is first started and until the electrode 20 and the tubular electrode 12 have become sulficiently heated by combustion to dry any oil coming in contact with their surfaces. It will be seen also that the annular fin 14 prevents oil from flowing downwardly on the outer surface of the tubular electrode 12 and then entering the tubular electrode.

If desired the spark plug may be constructed as illustrated in Figure 3 wherein the shell is designated by the numeral 40 and is provided with a tubular electrode 42. In. this case the tubular electrode l2 is not provided with an annular fin as in the case of the construction illustrated in Figure 2 and this form of invention is especially designed for use where the spark plug is not exposed to the splashing of oil due to the reciprocation of the piston in the cylinder.

The stem 17 may be provided with an in.- tegral concavo-convex baflle and electrode 48' having its outer edge formed with an annular electrode or flange 49 which cooperates with the forward end of the tubular electrode 42 in the formation of an annular spark gap. In this case also the inner side of the shell is provided with an inwardly projecting annular rib 50 beveled to an edge and directed downwardly so as to obstruct the entrance of oil and to allow of the free discharge of the same. The stem is pro- As the invided rearwardly of the concave-convex member 48 with an annular enlargement 52 the forward side of which is extended at right angles to the axis of the stem while the rear side is inclined outwardly.

It will be seen that one of the most important features of the invention resides in the fact that theaconcavo-convex electrode in advance of the tubular shell is of a greater diameter than the tubular electrode so that oil splashing rearwardly will not be permitted to enter the tubular electrode and herein lies one of the most important features of the invention. H

Furthermore convex surface on-the upper or rear side of the electrode 20' causes the spark to spread over a wide area in the combustion chamber and thereby assurescomplete combustion of the fuel.

The usual packing means and nuts therefor may be employed and it might be stated that in the form of the invention illustrated in Figure 3 the packing may be varied as to thickness to provide for the adjustment of the spark gap.

The foregoing illustrates that the invention forming the subject matter of this application is capable of a wide variety of mechanical expressions and it is therefore to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same and that such minor changes in arrangement and construction of parts may be made as will remain within the spirit of the invention and the scope of what is claimed.

Having thus described the invention, what is claimed is 1. A spark plug comprising a shell having a tubular electrode, a stem extending centrally through the shell and having its forward end provided with a combined elec trode and concavo-convex baffle, the edge portion of said combined electrode and concavo-convex baffle being provided with a flat annular flange arranged in advance of said tubular electrode and being greater in diameter than the tubular electrode and extending beyond the sides of the tubular elecinclined.

ROY LITTRELL STOVER. 

